ABSTRACT
Facial nerve paresis is an uncommon but concerning condition in the pediatric population. The function and anatomy of the facial nerve is complex, and injuries to this structure may be associated with devastating physiological and psychological implications for the affected child and family. The purpose of this paper was to report a case involving a six-year-old Caucasian female who suffered a blunt traumatic injury to the orofacial region resulting in partial paralysis of the seventh cranial nerve. Following the injury, the child was unable to fully elevate the corner of her mouth. The deficit occurred immediately, and she experienced a prolonged course of recovery.
Subject(s)
Facial Nerve Injuries/complications , Facial Paralysis/etiology , Wounds, Nonpenetrating/complications , Child , Female , HumansABSTRACT
Gal4 is the prototypical Zn2Cys6 binuclear cluster transcriptional regulator that binds as a homodimer to DNA containing inverted CGG half-sites. Leu3, a member of this protein family, binds to everted (opposite polarity to inverted) CGG half-sites, and an H50C mutation within the Leu3 Zn2Cys6 binuclear motif abolishes its transcriptional repression function without impairing DNA binding. We report the X-ray crystal structures of DNA complexes with Leu3 and Leu3(H50C) and solution DNA binding studies of selected Leu3 mutant proteins. These studies reveal the molecular details of everted CGG half-site recognition, and suggest a role for the H50C mutation in transcriptional repression. Comparison with the Gal4-DNA complex shows an unexpected conservation in the DNA recognition mode of inverted and everted CGG half-sites, and points to a critical function of a linker region between the Zn2Cys6 binuclear cluster and dimerization regions in DNA binding specificity. Broader implications of these findings are discussed.
